Initial travelling wavefront-based bus zone protection scheme

摘要

A high-speed busbar protection scheme based on initial travelling wavefronts is presented in this study. The aerial mode current travelling waves (TWs) across all lines connected to the busbar are calculated using Karenbauer transformation. Thereafter, the polarity and magnitude of wavelet transform modulus maximas of line current appearing after fault inception are analysed for fault zone and faulty phase identification. Its performance has been evaluated by modelling an existing 750 kV Indian substation in PSCAD/EMTDC software package. The simulation results reveal that the proposed scheme provides better stability for external faults and higher reliability in case of internal faults in comparison with conventional low-impedance busbar differential protection scheme (87B). Moreover, it remains immune to the current transformer saturation problems. In the end, comparative evaluation of the proposed scheme with the existing busbar protection schemes proves its superiority in terms of stability against external faults, sensitivity for internal faults, computational obligations, and communication requirements.